Ultraviolet sterilizer



FIG. 1 is a front, right side and top perspective view of an ultraviolet sterilizer showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines in the drawing depict portions of the ultraviolet sterilizer that form no part of the claimed design. 

CLAIM The ornamental design for an ultraviolet sterilizer, as shown and described. 